Subject: Re: [linux-audio-dev] Re: chebychev
From: Tim Goetze (tim_AT_quitte.de)
Date: Fri Nov 01 2002 - 18:47:04 EET
Steve Harris wrote:
>On Fri, Nov 01, 2002 at 03:13:28 +0100, Tim Goetze wrote:
>> >Blackman-Harris has the best sidelobe rejection, which is probably what we
>>
>> just to make sure we're talking about the same thing:
...
>I have:
...
the difference between the two is next to nothing, mostly a DC
offset. i'll use yours for the next FTs. is that 'Harris' as in
'S.W.Harris'? ;)
>Well, I think its best to develop with maximum wuality, then when its
>working, work out how much we can reduce the CPU cost and still have it
>sound good.
agree. though it's always good to keep in mind what is costly
and what is quick when choosing an implementation approach.
>> good god. know an alternative source for calculating the
>> coefficients? Bill?
>
>I have some text books that will have it in, I can compare that to NR.
after some NR 5-10 reading, it looks to me like harmonic_gen is
missing the work pcshft() from the book text is performing, yet
its output seems well-scaled.
it just occurred to me that it may be feasible to skip the
coefficient calculation in realtime by simply storing these
instead of harmonic amplitude tables. makes lerping difficult
though.
tim
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